1. Field of the Invention
This invention relates to a multi-chip package type semiconductor device, in which a plurality of semiconductor chips are mounted in the same package.
2. Description of the Related Art
Known semiconductor devices of the multi-chip package type are illustrated in FIGS. 1 and 2. In FIG. 1, semiconductor chips 11 used for example as LSI memories are mounted on a bed 12 made, for example, of a Fe(42 wt %)-Ni alloy via an alumina film 13 and an aluminum film 14. Interconnection between the semiconductor chips 11 is effected by a bonding wire 15, using the aluminum film 14 on the alumina film 13 as a wiring layer. Interconnection between each semiconductor chip 11 and a lead 16 is likewise by way of the bonding wire 15, using the aluminum film 14 on the alumina film 13 as a wiring layer.
In the device shown in FIG. 2, semiconductor chips 22 are mounted on a wiring substrate 23.sub.1 located beneath a bed 23.sub.2 via bumps 21. The provision of the bumps 21 disallows the semiconductor chips to be directly connected to the elements constituting the package. In FIG. 2, reference numeral 24 represents an aluminum fin, 25 an adhesive of high heat-conductivity, 26 a lead, 27 a mullite flange, 28 an alumina cap, 29 a sealing adhesive, and 30 a sealing adhesive.
Turning to the known device illustrated in FIG. 1, the alumina film interposed between the chips 11 and the bed 12 results in poor heat removing characteristics from the chips.
Referring again to FIG. 2, while the heat removing rate of the structure ranging from the beds 23.sub.1, 23.sub.2 to the aluminum fin 24 is high, they are low in regard to the heat generated at the semiconductor chips because of the bump 21 intervening between the chips 22 and the bed 23.sub.1.
Measures associated with the removing of the chip-generated heat in such known devices have been insufficient and have resulted in the elevated temperature of the chips, with an adverse effect on circuit functioning.